Method for preparing silicon tetrafluoride and anhydrous hydrogen fluoride from sodium fluosilicate acidified by sulfuric acid

A technology of anhydrous hydrogen fluoride and silicon tetrafluoride, which is applied in the direction of fluorine/hydrogen fluoride, silicon halide compounds, halosilane, etc., can solve the problems of high cost, high energy consumption, complicated process, etc., and achieve low environmental load and high-efficiency utilization , high environmental benefits

Inactive Publication Date: 2011-01-19
YUNNAN CHEM RES INST
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  • Abstract
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  • Application Information

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Problems solved by technology

[0003] At present, the production methods of hydrofluoric acid in the world are almost all high-cost, high-energy-consuming, and complex fluorite production processes, and the fluorite resources consumed are extremely limited.
There is no research and industrial test report on the production of hydrofluoric acid from fluosilicic acid and its sodium salt, a by-product of the phosphate compound fertilizer industry, in China; Synthetic calcium fluoride (fluorite) developed by the State Administration of Civil Affairs, and then produce hydrofluoric acid according to the traditional fluorite process. The ke...

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  • Method for preparing silicon tetrafluoride and anhydrous hydrogen fluoride from sodium fluosilicate acidified by sulfuric acid
  • Method for preparing silicon tetrafluoride and anhydrous hydrogen fluoride from sodium fluosilicate acidified by sulfuric acid
  • Method for preparing silicon tetrafluoride and anhydrous hydrogen fluoride from sodium fluosilicate acidified by sulfuric acid

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Embodiment 1

[0029] At a temperature of 100°C, add 100kg of sodium fluorosilicate and an excess of 20% sulfuric acid into the reactor and stir for 1 hour. The stirring rate is controlled at 200rpm and the concentration of sulfuric acid is 95%. Silicon tetrafluoride gas is obtained, and hydrogen fluoride remains in the solid residue. Among them, the decomposition rate is 49.7%, and the fluorine escaped into the gas phase accounts for 33.1% of the content of sodium fluorosilicate. Then the temperature was raised to 160°C, and hydrogen fluoride gas escaped. The two gases are strictly collected after dust removal, cooling, drying, refining and compression.

Embodiment 2

[0031] At 120°C, add 120kg of sodium fluorosilicate and an excess of 30% sulfuric acid into the reaction kettle for 1.2h, the stirring rate is controlled at 240rpm, and the concentration of sulfuric acid is 97%, to obtain silicon tetrafluoride gas, and hydrogen fluoride remains in the solid residue Among them, the decomposition rate is 56.9%, and the fluorine escaped into the gas phase accounts for 39.4% of the content of sodium fluorosilicate. Then the temperature was raised to 170°C, hydrogen fluoride gas escaped. The two gases are strictly collected after dust removal, cooling, drying, refining and compression.

Embodiment 3

[0033] At a temperature of 140°C, add 150kg of sodium fluorosilicate and excess 50% sulfuric acid into the reactor for 1.5h reaction, control the stirring rate at 300rpm, and sulfuric acid concentration of 98%, to obtain silicon tetrafluoride gas, and hydrogen fluoride remains in the solid residue Among them, the decomposition rate is 77.5%, and the fluorine escaped into the gas phase accounts for 51.2% of the content of sodium fluorosilicate. Then the temperature is raised to 180°C, and hydrogen fluoride gas escapes. The two gases are strictly collected after dust removal, cooling, drying, refining and compression.

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Abstract

The invention provides a method for preparing silicon tetrafluoride and anhydrous hydrogen fluoride from sodium fluosilicate acidified by sulfuric acid, which relates to the technical field of fluorine chemical industry, in particular to a method for preparing silicon tetrafluoride gas and anhydrous hydrogen fluoride gas by reaction of sodium fluosilicate and sulfuric acid. The method of the invention comprises the following steps: (a) stirring sodium fluosilicate and excessive sulfuric acid at the temperature lower than 150 DEG C for reacting to obtain silicon tetrafluoride gas, wherein hydrogen fluoride remains in solid residues; (b) dedusting, cooling, drying, refining and compressing the silicon tetrafluoride gas generated in the step (a) to obtain high-purity silicon tetrafluoride gas; (c) continuously heating to 200 DEG C to enable the hydrogen fluoride gas to escape; and (d) dedusting, cooling, drying, refining and compressing the hydrogen fluoride gas escaping in the step (c) to obtain the anhydrous hydrogen fluoride (AHF) gas. The invention enables the specific fluorine and silicon resources of phosphate fertilizer enterprises to be fully and efficiently utilized.

Description

technical field [0001] The invention relates to the technical field of fluorine chemical industry, in particular to a method for preparing silicon tetrafluoride and anhydrous hydrogen fluoride gas by reacting sodium fluorosilicate and sulfuric acid. Background technique [0002] Silicon tetrafluoride is an electronic special gas used in semiconductor and optical fiber processing applications, and is an important component in the ion implantation method used in the manufacture of silicon-based semiconductor devices. Silicon tetrafluoride will have broad application prospects in the microelectronics industry. Anhydrous hydrogen fluoride (AHF) is widely used in atomic energy, chemical industry, petroleum and other industries. It is a strong oxidant and a basic raw material for the production of elemental fluorine, various fluorine refrigerants, inorganic fluorides and organic fluorides. [0003] At present, the production methods of hydrofluoric acid in the world are almost al...

Claims

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Application Information

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IPC IPC(8): C01B33/107C01B7/19
Inventor 张宗凡梁雪松肖勇杨亚斌吴立群
Owner YUNNAN CHEM RES INST
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